(a) Unless otherwise provided, all criminal prosecutions whether for felony, misdemeanor or infraction shall be commenced by the filing of an information or the return of an indictment. Prosecution by information shall be commenced before a magistrate having jurisdiction of the offense alleged to have been committed unless otherwise provided by law.

(b) Unless otherwise provided, no information shall be filed before a magistrate charging the commission of a felony or class A misdemeanor unless the prosecuting attorney shall first authorize the filing of such information. This restriction shall not apply in cases where the magistrate has reasonable cause to believe that the person to be charged may avoid apprehension or escape before approval can be obtained.